Parmenides
He argued that reality is a single, unchanging, and eternal being, and that change is an illusion.
Most quoted
"The only roads of inquiry that are to be thought of: one, that it is and that it is impossible for it not to be, is the path of Persuasion (for she attends upon Truth); the other, that it is not and that it must not be, that I tell you is a path wholly unlearnable."
— from On Nature
"But since all things have been named light and night, and the names corresponding to their powers have been assigned to these things and to those, everything is full of light and obscure night together, of both equally, since neither has any share of nothing."
— from On Nature
"The only roads of enquiry there are to think of: one is that it is and cannot not be, this is the path of Persuasion (for she attends upon truth), the other, that it is not and needs must not be, this I tell you is a path wholly unknowable."
— from On Nature, -475
All quotes by Parmenides (130)
Nor is it divisible, since it is all homogeneous; and there is no more of it in one place and less in another, to prevent it from cohering, but it is all full of being.
Therefore, it is entirely inviolate; for what is has no deficiency which might separate it from holding to what is.
And it is all one to me where I begin; for I shall return there again.
For this view can never predominate, that that which is not exists.
There is a way which is and a way which is not.
The one way, that it is and cannot not-be, is the path of Persuasion, for it attends upon Truth.
The other, that it is-not and that needs must not-be, that I tell you is a path wholly unlearnable, for you could not know what is-not (for that is impossible) nor utter it.
Thus, generation is extinguished and destruction unheard of.
It is not lacking; if it were, it would lack everything.
Since, then, it has a furthest limit, it is complete on every side, like the mass of a well-rounded sphere, equally balanced from the centre in every direction.
For there is not, nor shall there be, anything else besides what is.
Fate has chained it so as to be whole and immovable.
Wherefore Justice does not loosen her fetters to permit generation or destruction, but holds it fast.
And since there is a furthest limit, it is perfected, like the bulk of a well-rounded sphere, from the middle equal every way.
For it is not permitted that what is should be incomplete; for it is not in need—if it were, it would need everything.
The thing that can be thought and that for the sake of which the thought exists is the same; for you cannot find thought without something that is, as to which it is uttered.
For thought and being are the same.
It is all one to me where I begin; for there again I shall return.
Thus, it must be completely or not at all.
Never will the force of conviction allow anything to come to be from what is not.
Contemporaries of Parmenides
Other Philosophys born within 50 years of Parmenides (-515–-450).